Experimental Investigation of Shock-Wave Diffuser Control of Shock Train

The shock train balances upstream and downstream pressures in the isolator, but excessive backpressure forces it upstream, risking inlet unstart. Shock-wave diffusers (SWDs) are proposed to suppress the shock train length and improve total pressure recovery. To suppress the shock train length, [Formula: see text] introduces multiple shock reflections, which transform the single shock train into a two-stage pressure-rise process. [Formula: see text] aims to reduce the total pressure loss by replacing a single strong shock with multiple weak shocks. SWDs were experimentally studied by parametric studies of the attack angle ([Formula: see text]), leading-edge position ([Formula: see text]), and length ([Formula: see text]). Results showed that [Formula: see text] ([Formula: see text]) reduced the shock train length by 4.9–19.8% under increasing backpressure, at the cost of a [Formula: see text] increase in total pressure loss. Conversely, [Formula: see text] ([Formula: see text]) improved the total pressure recovery coefficient by 1.1–4.7% as backpressure increased, while limiting the shock train length increase to no more than 1.5%. Consequently, SWDs provide a means to achieve specific performance gains at quantifiable costs, allowing for a deliberate choice between minimizing shock train length and maximizing total pressure recovery.